Have you looked at the weather? That time of year, it may be a little bit cold, and a little bit rainy still. That may be why you're having a hard time finding a tour.... but then again, I'm just speculating. It seems like they're having a harder than normal winter out there in Italy... maybe just plan for a trip and see how the weather is. Then if it's crap weather, you can stick to the trains, and if it's good weather, you can find a bike shop in the area and see if you can rent bikes for a day or two.